1. Field of the Invention
The invention relates to a method of sewing at least one supplementary part on a workpiece by a seam by use of a sewing machine that is drivable by an electric driving motor, which is provided with a computer-equipped control unit and has an external operating switch to be actuated by an operator for triggering a sewing operation.
2. Background Art
WO 00/66 825 teaches a so-called computer-based sewing workstation by means of which to sew sleeve parts into a jacket part in a given method.
DE 40 25 103 A1 discloses to apply, on a workpiece, an identification in the form of a barcode. It further teaches to provide the outer edge of the workpiece with marks in the form of notches that serve to make optically overlap two workpieces that are to be sewn together.
Sewing technology comprises fields of application in which supplementary or small parts that are not articles to be sewn together have to be sewn on a workpiece. For instance, the manufacture of vehicle seat covers requires various supplementary parts to be sewn on at varying distances; these parts may for example be strips of the cross-sectional shape of a hook and of a comparatively soft plastic material the needle of a sewing machine may pass through easily, by means of which to hook and stretch the seat cover or part of the seat cover on to a seat frame. Difficulties reside in keeping the correct sequence of the supplementary parts and joining them to the workpiece at the correct given place.
Furthermore, it is conceivable that only a single supplementary part has to be sewn on a workpiece at a certain place and that varying supplementary parts have to be joined alternately to varying workpieces. This too requires an operator""s full concentration, which does of course not go without errors.
It is an object of the invention to embody a method of the generic type such that during a sewing job, an operator""s errors in the selection of supplementary parts are widely precluded.
According to the invention, this object is attained by the following features: input of a workpiece identification that is applied to the workpiece into the computer and activation of a sewing program out of a plurality of sewing programs stored in the computer, with each sewing program including data for allocation of a given supplementary part; insertion of the workpiece into the sewing machine; seizure of the supplementary part by the operator and placement thereof on the workpiece; input of an identification that is applied to the supplementary part into the computer; release of the operating switch in case of conformity, with the data included in the activated sewing program, of the workpiece identification and of the identification of the supplementary part that is to be sewn on by the seam; and production of the seam by the supplementary part being sewn on the workpiece. It is important that the workpiece be identified first and that the supplementary part of the sewn on also be identified in this process. The sewing operation may only start when the operator has added the correct supplementary part and when this has been identified as being the correct part.
The feature which consists in the use of a screen that is allocated to the computer and in imaging, on the screen, the supplementary part to be sewn on the workpiece helps facilitate the operator""s job of seizing the correct supplementary part as programmed for an ensuing sewing operation.
In keeping with the advantageous further development which consists in the use of a screen that is allocated to the computer and in imaging the workpiece together with the to-be-sewn-on supplementary part at a place provided therefor on the workpiece, the screen also displays the workpiece together with any supplementary part to be sewn on subsequently.
Various sewing sequences are carried out in further advantageous embodiments.
Details of the invention will become apparent from the ensuing description, taken in conjunction with the drawings.